That's the number that governs selectivity coordination in a distribution panel. Only magnetic tripping operation (no thermal bimetal) means the part responds purely to short-circuit current; it does not provide overload protection. That design suits it for circuits where overload protection is handled upstream or by a separate device — typical in motor feeder protection where the contactor and overload relay do the thermal work.
Combined terminals top and bottom accept solid or stranded conductors from 0.75 up to 35 mm², with screw-terminal torque 2.5 to 3.5 N·m. Sealable cover and touch protection are standard — panel builders can lock the setting and meet IP20 with conductors connected.